Integrated metabolomic and transcriptomic analysis reveals the regulatory mechanisms of flavonoid and alkaloid biosynthesis in the new and old leaves of Murraya tetramera Huang.

BACKGROUND: Murraya tetramera Huang is a traditional Chinese woody medicine. Its leaves contain flavonoids, alkaloids, and other active compounds, which have anti-inflammatory and analgesic effects, as well as hypoglycemic and lipid-lowering effects, and anti-tumor effects. There are significant differences in the content of flavonoids and alkaloids in leaves during different growth cycles, but the synthesis mechanism is still unclear. RESULTS: In April 2021, new leaves (one month old) and old leaves (one and a half years old) of M. tetramera were used as experimental materials to systematically analyze the changes in differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) with transcriptomics and metabolomics technology. This was done to identify the signaling pathways of flavonoid and alkaloid synthesis. The results showed that the contents of total alkaloids and flavonoids in old leaves were significantly higher than those in new leaves. Thirteen flavonoid compounds, three isoflavone compounds, and nineteen alkaloid compounds were identified, and 125 and 48 DEGs related to flavonoid and alkaloid synthesis were found, respectively. By constructing the KEGG (Kyoto Encyclopedia of Genes and Genomes) network of DEGs and DAMs, it was shown that the molecular mechanism of flavonoid biosynthesis in M. tetramera mainly focuses on the "flavonoid biosynthetic pathway" and the "flavonoid and flavonol biosynthetic pathway". Among them, p-Coumaryl alcohol, Sinapyl alcohol, Phloretin, and Isoquercitrin were significantly accumulated in old leaves, the up-regulated expression of CCR (cinnamoyl-CoA reductase) might promote the accumulation of p-Coumaryl alcohol, upregulation of F5H (ferulate-5-hydroxylase) might promote Sinapyl alcohol accumulation. Alkaloids, including indole alkaloids, pyridine alkaloids, imidazole alkaloids, and quinoline alkaloids, were significantly accumulated in old leaves, and a total of 29 genes were associated with these substances. CONCLUSIONS: These data are helpful to better understand the biosynthesis of flavonoids and alkaloids in M. tetramera and provide a scientific basis for the development of medicinal components in M. tetramera.

Preservative effects of Osmanthus fragrans flower flavonoids on fresh-cut Yuluxiang pear.

Osmanthus fragrans flower flavonoids (OFFF) possess superior antioxidant and antibacterial activities. However, scant information exists on the efficacy of these secondary metabolites as preservatives for fresh-cut fruits and vegetables. Here, OFFF were tested as a natural preservative for the first time in fresh-cut Yuluxiang pear (Pyrus bretschneideri Rehd.) to assess effects on fruit quality. OFFF-treated samples showed significant retention of firmness, titratable acid, soluble solid content, and weight. Moreover, OFFF maintained the original fruit color, inhibited the decline of total phenol, reducing power and 2,2-diphenyl-1-picrylhydrazyl radical scavenging power, and diminished polyphenol oxidase and peroxidase oxidase activities. Furthermore, OFFF treatment effectively inhibited microbial growth. OFFF-treated samples also displayed better sensory quality. Considering cost and effectiveness, the most suitable concentrations of OFFF extract for fresh-cut Yuluxiang pear preservation were 0.7 and 0.9 mg/mL. The results indicate that OFFF treatment may be a potent strategy to inhibit browning and enhance nutritional properties of fresh-cut pear fruit.

Semi-supervised wildfire smoke detection based on smoke-aware consistency.

The semi-transparency property of smoke integrates it highly with the background contextual information in the image, which results in great visual differences in different areas. In addition, the limited annotation of smoke images from real forest scenarios brings more challenges for model training. In this paper, we design a semi-supervised learning strategy, named smoke-aware consistency (SAC), to maintain pixel and context perceptual consistency in different backgrounds. Furthermore, we propose a smoke detection strategy with triple classification assistance for smoke and smoke-like object discrimination. Finally, we simplified the LFNet fire-smoke detection network to LFNet-v2, due to the proposed SAC and triple classification assistance that can perform the functions of some specific module. The extensive experiments validate that the proposed method significantly outperforms state-of-the-art object detection algorithms on wildfire smoke datasets and achieves satisfactory performance under challenging weather conditions.

Phylogenetic studies of magnoliids: Advances and perspectives.

Magnoliids are the largest flowering plant clades outside of the eudicots and monocots, which are distributed worldwide and have high economic, ornamental and ecological values. Eudicots, monocots and magnoliids are the three major clades of Mesangiospermae, and their phylogenetic relationship is one of the most interesting issues. In recent years, with the continuous accumulation of genomic information, the evolutionary status of magnoliids has become a hot spot in plant phylogenetic research. Although great efforts have been made to study the evolution of magnoliids using molecular data from several representative species such as nuclear genome, plastid genome, mitochondrial genome, and transcriptome, the results of current studies on the phylogenetic status of magnoliids are inconsistent. Here, we systematically describe the current understanding of the molecular research on magnoliid phylogeny and review the differences in the evolutionary state of magnoliids. Understanding the research approaches and limitations of magnoliid phylogeny can guide research strategies to further improve the study of the phylogenetic evolution of magnoliids.

The red flower wintersweet genome provides insights into the evolution of magnoliids and the molecular mechanism for tepal color development.

Wintersweet (Chimonanthus praecox) is one of the most important ornamental plants. Its color is mainly determined by the middle tepals. However, the molecular mechanisms underlying the intriguing flower color development among different wintersweet groups are still largely unknown. In addition, wintersweet belongs to magnoliids, and the phylogenetic position of magnoliids remains to be determined conclusively. Here, the whole genome of red flower wintersweet, a new wintersweet type, was sequenced and assembled with high quality. The genome comprised 11 super-scaffolds (chromosomes) with a total size of 737.03 Mb. Based on the analyses of the long branch attraction, incomplete lineage sorting, sparse taxon sampling, and other factors, we suggest that a bifurcating tree may not fully represent the complex early diversification of the angiosperms and that magnoliids are most likely sister to the eudicots. The wintersweet genome appears to have undergone two whole-genome duplication (WGD) events: a recent WGD event representing an independent event specific to the Calycanthaceae and an ancient WGD event shared by Laurales. By integrating genomic, transcriptomic, and metabolomic data, CpANS1 and the transcription factor CpMYB1 were found to play key roles in regulating tepal color development, whereas CpMYB1 needs to form a complex with bHLH and WD40 to fully perform its regulatory function. The present study not only provides novel insights into the evolution of magnoliids and the molecular mechanism for flower color development, but also lays the foundation for subsequent functional genomics study and molecular breeding of wintersweet.

Silica nanoparticles capture atmospheric lead: implications in the treatment of environmental heavy metal pollution.

Lead (Pb) contamination in the air is a severe global problem, most notably in China. Removal of Pb from polluted air remains a significant challenge. It is unclear what potential effects silica nanoparticles (SiNPs) exposure can have on atmospheric Pb. Here we first characterized the features of SiNPs by measuring the particle size, zeta potential and the specific surface area of SiO(2) particles using a Nicomp 380/ZLS submicron particle sizer, the Brunauer-Emmett-Teller (BET) method and transmission electronic microscopy (TEM). We measured the content of the metal Pb adsorbed by SiNPs exposed to two Pb polluted electric battery plants using inductively coupled plasma mass spectrometry (ICP-MS). It is found that SiNPs exposed to two Pb polluted electric battery plants absorb more atmospheric Pb compared to either blank control or micro-sized SiO(2) particles in a time-dependent manner. This is the first study demonstrating that SiNPs exposure can absorb atmospheric Pb in the polluted environment. These novel findings indicate that SiNPs have potential to serve as a significant adsorbent of Pb from industrial pollution, implicating a potentially novel application of SiNPs in the treatment of environmental heavy metal pollution.

[Rare earth elements in marine organisms from Shenzhen coastal region].

OBJECTIVE: A sensitive quantificational method was set up to determine the rare earth elements (REE) in marine organisms from Shenzhen coastal region. Characteristics of REE contents and distribution patterns of REE were analyzed. METHODS: A total of 60 samples of marine organisms were collected at six sampling sites in the Shenzhen coastal region. Concentrations of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er, Ho, Tm and Lu in the samples were determined by inductively coupled plasma-mass spectrometry (ICP-MS). The quantificational method was validated with standard reference material GBW 10016 (tea-leaf). RESULTS: The mean concentrations of total REE in mollusk, barnacle, shrimp and fish were (2.66 +/- 2.28), (4.69 +/- 1.32), (0.03 +/- 0.03) and (0.07 +/- 0.02) microg/g, respectively. Enrichment of light REE (LREE) over heavy REEs (HREE) were observed for all tested marine organisms. CONCLUSION: (1) The chondrite-normalized distribution of REE for mollusk, barnacle and shrimp showed a similar pattern with those of sediment in northern continent slopes of the South China Sea, soils of Hong Kong and the Mainland (mean), while small differences were observed for fish. (2) Consumers would be faced with risk to eat the bivalves. (3) Barnacle and oyster were suggested here as bio-marker for REE in marine environment due to the high potential of REE enrichment, similar chondrite-normalized distribution to marine sediment and adhering life style of the two kind of animals.

[Total arsenic in marine organisms determined by graphite furnace atomic absorption spectrometry].

OBJECTIVE: To establish the method of total arsenic in marine organisms determined by graphite furnace atomic absorption spectrometry (GFAAS) in order to detect the contents of total arsenic in marine organisms around the coast of Guangdong Province. METHODS: The marine organisms samples were digested by HNO3 in high-pressure closed-vessel, the contents of total arsenic were analyzed by GFAAS with PdCl2-NiNO3 as matrix modifier. RESULTS: The calibration curve showed good linearity in the range of 0 - 40 microg/L with correlation coefficient of 0.997, the detection limits were 0.030 mg/kg and the precisions ranged from 3.7% to 5.1%, and the results of analyzing standard materials were in the certificate values. The contents of total arsenic ranged from 0.09 mg/kg to 12.58 mg/kg wet weight in the 99 tested samples and the average contents were 1.85 mg/kg. CONCLUSION: The interference of matrix could well be eliminated by the method which could be precise and accurate, the marine organisms around the coast of Guangdong Province were polluted by arsenic in different levels.

1,3,4,6-Tetra-chloro-7,7-bis-(4-chloro-phen-yl)bicyclo-[4.2.0]oct-3-ene-2,5-dione.

The title compound, C(20)H(10)Cl(6)O(2), a quinone derivative, was obtained by the irradiation of 2,3,5,6-tetra-chloro-benzo-quinone and 4,4'-(ethene-1,1-di-yl)bis-(chloro-benzene). The six- and four-membered rings are fused in a cis configuration. The dihedral angle between them is 53.4 (3)°.

[Effect of the long-term intake of yttrium in drinking water on trace elements in F1 generation mice].

The effects of the long-term intake of yttrium on trace elements in tissues and yttrium in brain of F1 generation mice were studied so as to elucidate some physiological function of the rare earths. The mice were fed with Y3+ (0, 23.25 mg/L, 2325.00 mg/L) dissolved water at different levels for seven months. The level of trace elements such as Cu, Cd, Pb and Y in brain and Se in brain, liver, spleen and kidney of F1 generation mice were measured by ICP-MS and atom fluorescent method. The results showed that, compared with control mice, significant changes in content of Se (P < 0.05) in spleen and Y (P < 0.05) in brain were observed, but no changes were found in content of Pb, Cd, and Cu in brain for the high dose group, and an increase was detected in content of Se(P < 0.05) in spleen for the low dose group, suggesting that long-term intake of Y3+ might enhance the absorption of Se in some tissue that might be one of the biological effect of rare earth and, Y3+ might enter young mammalian brain.